Turkish researchers have found evidence of widespread West Nile Virus (WNV) activity in the country.

WNV is a mosquito-borne flavivirus with significant impact on human and animal health. It has recently shown an expanded zone of activity globally.

University-based researchers in Turkey set about investigating the frequency and distribution of WNV infections in several mammal and bird species in which there had been previous evidence of the virus circulating.

They worked in 15 provinces across Turkey during 2011–2013. In addition, mosquito research was extended to four districts of the Turkish Republic of Northern Cyprus.

WNV exposure was found in humans, horses, sheep and ducks from Mersin, Sanliurfa, Van and Kars provinces of Turkey.

Field-collected mosquitoes from 92 sites at 46 locations were evaluated for evidence of the virus, with neutralizing antibodies identified in 10.5 percent of the 1180 samples studied and detected in all species evaluated.

Viral RNA was detected in horses in all locations, with an overall rate of 5.9 percent and a significantly higher rate of positivity in Mugla province (30.6 percent)

The researchers said their findings indicated widespread WNV activity in Turkey, in Eastern Thrace and Mediterranean-Aegean regions, as well as Southeastern and Northeastern Anatolia.

“Our findings indicate virus exposure in humans and various animals in previously unexplored regions as well as a high rate of virus circulation in equine blood samples during the mosquito season,” they wrote in their findings, published in the open-access journal, PLos Neglected Tropical Diseases.

Field-captured mosquito specimens demonstrated the presence of major WNV vectors among the 15 species identified.

WNV demonstrates an extensive zone of distribution throughout Africa, the Middle East, southern Europe, western Russia, southwestern Asia, and Australia.